Collapsible stroller

ABSTRACT

A collapsible child&#39;s stroller with a handle frame (30), a front wheel frame (10) and a rear wheel frame (20), mutually connected at a hinge joint (12, 22, 42) for mutual angular displacement between folded and unfolded configurations. The hinge joint has two spaced apart, parallel hinge axes, about which the frames (10, 20, 30) mutually rotate. The stroller is further provided with a locking element (43, 44) moveable between a locked position in which the frames (10, 20, 30) are locked in the unfolded configuration, and an unlocked position allowing the frames (10, 20, 30) to rotate to the folded configuration. The locking element (43, 44) moves in a direction traverse to the parallel hinge axes to better transfer loads between the frames.

FIELD OF THE INVENTION

The present invention relates to strollers for babies, toddlers and young children. In particular, the invention relates to strollers with collapsible frames that fold into a compact configuration for storage and portability.

BACKGROUND OF THE INVENTION

Strollers are a well known and common way of transporting babies or young children. However, due to their size, strollers typically have collapsible frames that fold into a more compact configuration for storage or to be stowed in a vehicle.

In an effort to achieve a more compact folded configuration, some collapsible strollers have particularly complex hinged and telescopic frame structures. While this may provide a compact folded form, the complexity of the frame increases the production costs. Furthermore, added complexity of the frame tends to weigh against a smooth and reliable folding mechanism. For parents of young children, this operation needs to occur as quickly and simply as possible.

Many countries have official design standards and regulations that apply to strollers. These require the frame to meet certain strength and rigidity thresholds while avoiding hazards such as finger traps and so on. The strength requirement specified by the official standards mean that steel or aluminium alloy are the traditional choices for frame material. However, from the perspective of material costs and high-volume production, polymer frames would be more desirable. Polymers have the added advantage of being lightweight, easily moulded into ergonomic shapes and coloured for greater aesthetic appeal. However, to meet the required strength and structural standards, the polymer would need to be an exotic composite and prohibitively expensive. Alternatively, a cheaper (and weaker) polymer would need to be formed in large cross sections which defeats the purpose of a compact collapsible stroller.

With these issues in mind, there is a need for a collapsible stroller with a predominantly polymer frame that meets the high strength and structural requirements of the official standards, while smoothly, simply and reliably collapsing into a compact folded form.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a collapsible stroller comprising:

-   -   a handle frame;     -   a front wheel frame;     -   a rear wheel frame; and     -   a hinge joint connecting the handle frame, the front wheel frame         and rear wheel frame for mutual angular displacement relative to         each other about two spaced parallel hinge metal axles, the         hinge joint having a locking element moveable between an         unlocked position allowing the handle, front wheel and rear         wheel frames to mutually rotate into a folded configuration, and         a locked position in which the handle, front wheel and rear         wheel frames are fixed in an unfolded configuration; wherein,     -   the locking element moves in a direction transverse to the two         parallel hinge axes.

The handle, front wheel and rear wheel frames are predominantly polymer made of a polymer material.

The Applicant has found that configuring the locking element such that its movement is transverse to the hinge axles allows the locking element itself to be a significant structural element of the stroller and in particular the main folding hinge. This allows the stroller to be predominantly polymer with reinforcement at a structurally crucial part.

The locking element can take a variety of forms, but is conveniently provided as a locking pin for ease of production and incorporation into the hinge joint. Traditionally, the main hinge mechanisms in collapsible strollers use a locking pin or equivalent structure which moves parallel to the hinge axis to lock two hinged frame members together. This is adequate for preventing relative rotation of two frame elements but does very little to transfer bending or axial loads between these elements. By configuring the locking pin such that it extends in a direction transverse to the hinge axis, it essentially becomes a significant load bearing element in its own right. In particular, it provides a load bearing element at the connection between two frame elements to transfer substantial loads therebetween. As the locking pin is transverse to the hinge axle (ie. axis). It can also be made physically larger and stronger without any impact on the overall size of the frame elements as it still comfortably fits within the frame element cross-sections.

Preferably, the locking pin is metallic and in a particularly preferred form the locking pin is steel. Preferably the locking pin has a minimum cross sectional dimension of 5 mm. Preferably, the locking pin is solid, as tubular locking pins would risk being crushed. Preferably the locking pin is at least 40 mm long and more preferably at least 55 mm long.

The hinge joint has at least two reinforced bearing surfaces adjacent the locking pin when in the locked position, such that structural loads are transferable between the reinforced bearing surfaces via the locking pin. Advantageously, the hinge joint's metal axles provide at least one of the reinforced bearing surfaces.

In one option, the other reinforced bearing surface is provided by (or at) a movable element, such as a metallic pin element, that moves into a load bearing position as the locking pin moves to the locked position and moves away from the load bearing position when the locking pin retracts from the locked position.

The hinge joint has a hinge housing of polymer material integrally formed with the polymer rear wheel frame, and the polymer handle frame has an integrally formed spur-gear formation for rotation about one of the hinge axles within the hinge joint, while the front wheel frame has an integrally formed polymer spur-gear formation rotatably mounted at the other of the hinge axles for meshing inter-engagement with the spur-gear formation of the handle frame. As per the invention, the locking pin is arranged to be received and slide within a two-section groove defined partially at the handle frame and partially at the front wheel frame. Preferably, the groove is partially defined within the spur-gear formation of the handle frame and partially defined within the spur-gear formation of the front wheel frame such that the section of the groove in the front wheel frame aligns with the section of the groove in the handle frame when in the locked position. Preferably, the locking pin is biased into the locked position, by a spring, within the section of groove defined by the handle frame.

Preferably, the hinge joint has a pin guide surface for sliding engagement with a distal end of the locking pin as the stroller folds and unfolds such that the pin guide surface limits movement of the locking pin when moving from the folded to the unfolded configuration. In a particularly preferred form, the front-wheel frame has a slide surface for receiving the end of the locking pin from the pin guide surface, and smoothly directing the locking pin to the section of the groove in the front-wheel frame that partially defines the locked position. Preferably, the pin guide surface and the slide surface have a common tangent at the point of transition where the pin guide surface hands-off the end of the locking pin to the slide surface. In a particularly preferred form, the locking pin is chamfered or rounded.

Preferably, the handle frame has a grip section and an unlocking actuator connected to the biased locking pin for retracting the locking pin into the unlocked position. Preferably, the direction of movement of the locking pin and the longitudinal extent of the handle frame are angled relative to each other by less than 45 degrees such that actuation of the unlocking actuator is a manual displacement in a direction broadly similar to the direction of movement of the locking pin.

In a particularly preferred form, the longitudinal extent of the handle frame, the rear-wheel frame and the front-wheel frame are substantially parallel in the folded configuration.

Preferably, the front-wheel frame has a front-wheel assembly and the rear-wheel frame has a rear-wheel assembly, the front-wheel assembly having a narrower wheel base than the rear-wheel assembly such that in the folded configuration, the front wheel assembly nests within the rear-wheel assembly.

In a related aspect, the handle frame, the rear-wheel frame and the front-wheel frame are formed from a glass fibre reinforced nylon material. Preferably, the glass fibre reinforced nylon material is a composite with 25% to 35% by weight of glass fibre.

In some embodiments, the rear wheel frame includes a braking mechanism to prevent rotation of the rear wheels, the rear wheel frame further comprising a brake actuator pedal configured for foot actuation of the brake mechanism such that the pedal can be moved between an engaged and dis-engaged position using the sole of the foot only. It will be appreciated that this prevents scuffing to the upper parts of any footwear or injury and discomfort to those with open toed footwear.

The invention will be described by way of example only with reference to a preferred embodiment illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of a collapsible stroller with child seat and hood fabric removed for clarity;

FIG. 2 is an exploded perspective of the collapsible stroller of FIG. 1;

FIG. 3 is an enlarged exploded perspective showing the top and left of the left-side hinge joint; 

1.-16. (canceled)
 17. A collapsible stroller, comprising: a front wheel frame, a rear wheel frame; a handle frame; a hinge joint that connects the front wheel frame and the rear wheel frame with the handle frame, wherein a locking element enables the stroller to be converted between folded and unfolded configuration, where in a spur-gear integrally formed with the handle frame meshes with a spur-gear integrally formed with the front wheel frame, further wherein the locking element slides within a two-section groove and where the hinge joint has at least two reinforced bearing surfaces adjacent to the locking element to allow structural loads to be transferable between the reinforced bearing surfaces and the locking element.
 18. The collapsible stroller according to claim 17, wherein the locking element is a metallic locking pin.
 19. The collapsible stroller according to claim 18, wherein the hinge joint has at least two reinforced bearing surfaces adjacent the locking element when in the locked position, such that structural loads are transferable between the reinforced bearing surfaces via the locking element.
 20. The collapsible stroller according to claim 19, wherein at least one of the at least two reinforced bearing surfaces is provided by a metal axle.
 21. The collapsible stroller according to claim 20, wherein another one of the at least two reinforced bearing surfaces is provided by a movable pin element located closely adjacent the metal axle of the front wheel frame and which is configured to move into a load bearing position when the locking pin moves to the locked position and moves away from the load bearing position when the locking pin retracts from the locked position.
 22. A collapsible stroller according to claim 21, wherein the movable pin element extends parallel to the metal axle of the front wheel frame and is guided in an arcuate slot about the front wheel frame axle.
 23. A collapsible stroller comprising: a predominantly polymer handle frame; a predominantly polymer front wheel frame; a predominantly polymer rear wheel frame; a hinge joint connecting the handle frame, the front wheel frame and a locking element at the hinge joint slidingly moveable between an unlocked position in which the handle frame, front wheel frame and rear wheel frame are enabled to mutually rotate into a folded configuration, and a locked position in which the handle, front wheel and rear wheel frames are fixed to each other in an unfolded configuration; wherein the hinge joint comprises a hinge housing of polymer material integrally formed with the polymer rear wheel frame, a spur-gear formation of polymer material integrally formed with the handle frame, the handle frame spur-gear formation configured for rotation about one of the hinge axles within the hinge joint, and a spur-gear formation of polymer material integrally formed with the polymer front wheel frame, the front wheel frame spur-gear formation configured for rotation about the other one of the hinge axles within the hinge joint and meshing with the handle frame spur-gear formation.
 24. The collapsible stroller according to claim 23, wherein the locking element is a metallic locking pin.
 25. The collapsible stroller according to claim 24, wherein the hinge joint has at least two reinforced bearing surfaces adjacent the locking element when in the locked position, such that structural loads are transferable between the reinforced bearing surfaces via the locking element.
 26. The collapsible stroller according to claim 25, wherein at least one of the at least two reinforced bearing surfaces is a metal axle.
 27. The collapsible stroller according to claim 26, wherein another one of the at least two reinforced bearing surfaces is provided by a movable pin element located closely adjacent the metal axle of the front wheel frame and which is configured to move into a load bearing position when the locking pin moves to the locked position and moves away from the load bearing position when the locking pin retracts from the locked position.
 28. A collapsible stroller according to claim 27, wherein the movable pin element extends parallel to the metal axle of the front wheel frame and is guided in an arcuate slot about the front wheel frame axle. 